Matthew Dolloff, 30, is being held for investigation of first-degree murder. 9News said he worked for the private security company Pinkerton.
“This remains an active investigation,” the Denver Police Department said in a tweet. “Any additional updates will be released as it becomes available.”
9News says Dolloff is a contractor who was accompanying one of its producers at the demonstrations Saturday at Civic Center Park. Far-right and far-left groups held dueling protests in the hours leading up the shooting.
Videos and photos of the shooting show Dolloff firing a single shot at a man after an altercation. It appears the man may have fired mace at Dolloff.
“It has been the practice of 9News for a number of months to hire private security to accompany staff at protests,” 9News reported.
The shooting victim was not named by authorities and died at a nearby hospital. But his son identified the man on Sunday to the Denver Post as Lee Keltner, a 49-year-old U.S. Navy veteran who operated a hat-making business in the Denver area.
“He wasn’t a part of any group,” Johnathon Keltner told the newspaper. “He was there to rally for the police department and he’d been down there before rallying for the police department.”
A woman who said she was the victim’s mother, Carol Keltner, wrote in a social media post that her son was killed after being shot in the head.
A decision on any charges will be up to the Denver District Attorney’s Office, police said. A spokesperson for District Attorney Beth McCann said Sunday that the arrest affidavit in the case remained sealed and referred further questions to the police.
It was not immediately clear if Dolloff had an attorney.
Denver police Division Chief Joe Montoya said two guns were found at the scene, as well as a Mace can.
Security guards in Denver are supposed to be licensed, with additional endorsements needed to carry a firearm or operate in plainclothes, according to rules for the industry adopted by the city in 2018.
In photos from Saturday’s shooting, Dolloff did not appear to be in uniform. His name does not show up on a city-run database that lists several thousand licensed security guards.
City officials say they are investigating.
“The Denver City Attorney’s Office will weigh any additional criminal charges related to the defendant possibly operating as an unlicensed security guard once the Denver Police Department completes its homicide investigation,” Ryan Luby, a spokesman for the Denver City Attorney’s Office, said in a written statement. “The CAO is also working with the Denver Department of Excise and Licenses to weigh disciplinary action against the security guard company for hiring and deploying an unlicensed guard, one without a license much less an armed endorsement.”
Representatives of Pinkerton did not immediately return email and telephone messages for comment.
The Associated Press contributed to this report.